The prior art engine (U.S. Pat. Nos. 8,109,244 B1 and U.S. Pat. No. 5,402,755), proposed by Waissi, is an internal combustion engine with opposed and aligned cylinders, called here the Waissi Engine. The Waissi Engine consists of at least one pair of aligned and opposed cylinders wherein a reciprocating double-headed piston is slidably mounted, and in which the double-headed piston axis intersects perpendicularly with the axis of a driveshaft. The reciprocating motion of the double-headed piston is transmitted to the driveshaft by a rotating crankdisk. The crankdisk is rigidly and off-centered mounted to the driveshaft, which is rotably mounted to a crankcase. The crankdisk outer perimeter forms a circle. The double-headed piston has two slots perpendicularly through its axis, one of which is to allow for a rotating movement of the crankdisk, and the other, to allow for the rotation of the driveshaft. The prior art further discloses that the double headed piston may be assembled from multiple components or parts, which form an integrated, rigid, piston structure.
In conventional prior art engines (V-, in-line, opposed) the metal to metal contact between the piston connecting-rod big-end and the crankshaft is avoided by creating hydrodynamic lubrication conditions in an oil film of the connecting-rod to crankshaft bearing. It is therefore, and in order to reduce friction and wear, highly desirable to create similar hydrodynamic lubrication conditions in the piston to crankdisk contact surface of the Waissi Engine, and, in particular, to provide for crankdisk rotation under hydrodynamic conditions.
The prior art improvement (SAE SP-1108, Paper No. 950090, Futuristic Concepts in Engines and Components, pp. 61-64, (1995)) to the Waissi Engine propose to reduce friction between the crankdisk annular bearing surface and piston internal bearing surfaces by a special bearing ring. Within this improvement the outer perimeter surface of the crankdisk acts as a bearing and slides inside the bearing ring. The crankdisk has a diameter and annular perimeter design that fits tightly but slidably inside the bearing ring. The bearing ring, with a diameter that fits in-between the piston slot bearing surfaces (or inside the piston slot), is intended to roll or slide on the piston slot bearing surface. The crankdisk perimeter and surface design correspond the conventional engine crankshaft—piston rod journal design to provide for hydrodynamic lubrication.
The prior art (U.S. Pat. No. 8,109,244 B1) improvement discloses specific designs for the crankdisk and bearing ring to provide for assembly as well as for holding the bearing ring in its designed location when the crankdisk rotates. The bearing ring is installed on the crankdisk to provide for hydrodynamic lubrication conditions between the crankdisk and the bearing ring, and for oil-splash lubrication between the bearing ring and the piston slot surface.
The prior art (U.S. Pat. No. 8,109,244 B1) discloses two specific distinct designs for the crankdisk-bearing combination. One of the designs consists of a machined or casted groove or depression on the crankdisk outer annular surface, in which one or both of the flanges or sides of the groove of the crankdisk are removable to allow for a flat I-profile bearing ring installation such that the bearing ring fits tightly but slidably in-between the flanges of the crankdisk annular bearing surface. The second, or alternative, design consists of a machined or casted groove on the inside surface of the bearing ring, forming a U-profile with flanges facing toward the center of the bearing ring, in which one or both of the flanges or sides of the groove are removable to allow for the U-profile bearing ring installation such that the crankdisk bearing surface fits tightly but slidably in-between the bearing ring flanges. Both designs propose modifications in form of casting or machining a U-profile on either the inside surface of the bearing ring or the annular outside surface of the crankdisk with one or both flanges or sides removable respectively. Both proposed designs provide for assembly as well as for holding the bearing ring in its designed location when the crankdisk rotates. Both proposed designs also provide for hydrodynamic lubrication condition between the crankdisk annular bearing surface and the bearing ring.
However, as summarized above, the prior art proposes only a bearing ring—crankdisk combination design that will require machining or casting a groove or depression on either the inside surface of the bearing ring or the outer annular surface of the crankdisk with one or both groove flanges removable to provide for assembly, as well as to hold the bearing ring in its designed place when the crankdisk rotates. The prior art proposed solution includes also an alternative utilization of roller- or ball bearings instead of a bearing ring. However, roller-, ball and other direct contact (metal-to-metal, or other direct solid material contact) bearings are not the subject of this invention.